Mostly the only rule is if your gonna take a job, do it.
you can take as many jobs as you like as well as apply. also just because you apply for a job doesn't mean you will get it, who ever i think is most qualified and who comes first will get the job. Please don't get mad over this; there will always be more jobs!
Your payment is sadly just the love of your forum admin for now as well as some rep points. more may come later :)
ok that is it for now, hope to hear from you soon!